Utilities
53
WDT LED Control
GPO25 of the 6300ESB is designed to control WDT LED. Two
features of the WDT LED are supported on cPCI-3840. WDT
LED lights or blinks.
X
WDT LED lights: Set bit 25 of GP 04H to 0. Bit 25
of GP 0CH determines the state of WDT LED.
(0=light, 1=dark)
X
WDT LED blinks: Set bit 25 of GP 04H to 0. Bit 25
of GP 18H enables WDT LED blinking function.
(0=function normally, 1=enable blinking) The high and low
times have approximately 0.5 seconds each.
WDT Programming Procedure
1. Set BIOS Setting in Integrated Peripherals\Onboard
Device Page Watch Dog Timer Item to “Enabled”.
2. Make sure WDT_TOUT# signal is functional. (Not
GPIO32 function).
3. Set WDT output enable, presecaler and interrupt type
into WDT configuration register.
4. Obtain control base from Base Address register.
5. Program Preload register’s value according to unlocking
sequence.
6. Set WDT timer mode into WDT Lock Register.
7. Enable WDT from WDT Lock register and program the
functionality of WDT LED.
To prevent the timer from causing an interrupt or driving
WDT_TOUT#, the timer must be reloaded periodically. The fre-
quency of reloads required is dependent on the value of the pre-
load values. To reload the down-counter, the register unlocking
sequence must be performed.
If the user wishes to disable WDT, set bit 1 of WDT Lock Register
to 0.
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